Bilstein's shock bodies are precision formed through a unique seamless extrusion process. This provides superior strength along with high finish tolerances that are usually associated with surgical instruments. The finished body is then mated with a solid, induction hardened steel chrome plated and polished shaft, machined valving components and highest quality seals. Combined with extreme attention to detail, Bilstein provides you with the closest thing to a hand built shock available today. Limited lifetime warranty.